The threshold voltage is set by output channel comprised of pulse generator, photoelectric coupler and F/V converter, and the detection result is input through photoelectric coupler.
利用可变频脉冲发生器、光电耦合器和F/V转换器组成输出通道，设定阀值；
A general model for fiber directional coupler with fiber Bragg gratings in its arms is presented. The output expression of any arm is obtained when input is from an arm.
提出了臂内含有光纤光栅的方向耦合器的一般模型，推导了任意端口输入时任何一端口的输出表达式。
应用推荐